QoR Dashboard & Trend Triage: Design Space

Design space exploration

For QoR Dashboard & Trend Triage, options trade QoR gain, risk, and schedule.

Option A — conservative

• Conservative constraints: helps predictability

• Risk: slower PPA gains

• Validate with: first-silicon safety

Option B — balanced

• Balanced QoR tuning: helps stable closure

• Risk: requires discipline

• Validate with: typical product mode

Option C — aggressive compile

• Aggressive compile push: helps fast timing recovery

• Risk: power/hold regressions

• Validate with: late schedule

Option D — structural change

• Structural RTL change: helps long-term fix

• Risk: schedule impact

• Validate with: recurring bottleneck

DESIGN SPACE — QoR Dashboard & Trend Triage
QoR gain <-> regression risk <-> schedule pressure

Design pitfalls

• Single-metric optimization

• No rollback path

• Weak run comparability

Tradeoff curve

BEFORE / AFTER QOR — QoR Dashboard & Trend Triage

QoR score
  0 |                     --- target zone
 -1 |        ● regression
 -2 |             ● baseline
 -0.5|                  ● after fix
    +----------------------------------> iteration

Validate timing + area + power, not one number.

Synthesis deep dive

Constraint hygiene determines whether synthesis QoR is trustworthy.

Concept diagram

CONSTRAINT FLOW

RTL intent -> synthesis SDC -> compile checks -> QoR dashboard -> review gate

Metric graph

QOR HEALTH

constraint lint pass   ███████████████
unconstrained count    ███
policy violations      ██

Reports and artifacts

• compile QoR

• unconstrained endpoints

• constraint lint

• policy audit log

Mini case study

Nightly WNS improved but unconstrained paths jumped; strict SDC lint restored true QoR picture.

Debug branches

• Diff SDC first

• Audit dont_touch scope

• Track unconstrained trend weekly

Senior review question

Ask: what evidence proves this QoR move is real and stable?

Key takeaways

• State exact run context (RTL, SDC, libs, switches) with every QoR claim.

• Re-run timing, area, and power regressions after each synthesis ECO.

Common pitfalls

• Comparing runs with mismatched constraints or library views.

• Timing-only fixes that violate power or area budgets.

• Skipping equivalence checks after structural changes.

Principal synthesis review addendum

QoR closure is a trend-management problem: dashboard baselines catch regressions early and keep optimization decisions tied to measurable outcomes.

Metric: WNS/TNS trend, area delta, dynamic/leakage trend, compile runtime